Sars, 1907
Short Description:
Chiridiella macrodactyla is an aetideid calanoid copepod known after female (2.35-2.65 mm in length).
Taxonomic Description:
Female. Total length 2.35-2.65 mm ( 3.15 mm after Deevey, 1974). Cephalothorax slightly less than 4 times longer than abdomen. A1 slightly longer than cephalothorax, 24-segmented. Ri A2 a little bit longer than half the length of Re A2. Ri2 A2 with 5 long and 3 short setae on internal and 6 setae on external lobe; coxo- and basipodite with 1 seta each. Ri2 Md with 3 setae. Mx1 with 2 setae on the third internal lobe, 5 on Ri, 4 on Re and 8 on external lobe; second internal lobe reduced. Mx2 with 1 (Sars, 1907; 1924), 2 (Sars, 1925) setae on the first (proximal) endite, 1 long and 1 short seta on third, and 2 spines of unequal length, arranged like pincers on the fourth endite. The longest of these spines is claw-like, prolonged and abruptly curved near its base with straight terminal part, internally it is covered with small spinules. Another spine shorter, thick and also slightly curved, covered with hairs internally. Fifth endite of Mx2 prolonged into spine-like projection, smoothly curved, distal part of Ri Mx2 rudimentary and presented by 2 thin setae. Ri1 Mxp by about one fourth of its length exceeding protopodite, latter with 2 setae in distal group; and Ri1 Mxp with 3 medial setae. P1 with one-segmented rami, Re with 1 external terminal spine, Ri lacking external lobe. Ri P2-P4 3-segmented, Ri P2 - one-segmented, Ri P3-P4 - 3-segmented.
Male unknown.
Remarks. The description of the species (Sars, 1907; 1924-25) is incomplete and sometimes contradictory (as in the case of description of Mx2 structure) and if to take into consideration the recent descriptions of few similar species of Chiridiella (Deevey, 1974) status of Ch. macrodactyla is not very clear. In the collections of the Zoological Institute, Russian Academy of Sciences, St. Petersburg 3 female specimens were found attributed to the present species. They have cephalon and Th1 incompletely separated and Ri P3-P4 if 3-segmented then indistinctly. They also differ of Ch. macrodactyla described before (Sars, 1924-25; Deevey, 1974) in details of Ri2 Md and Mxp protopodite setation. It is necessary to note that Ch. macrodactyla needs further revision that may be possible only after getting some additional material. Very close to Ch. macrodactyla are Ch. ovata Deevey, 1974 and Ch. abyssalis Brodsky, 1950.
Geographical distribution:
Most possible distribution areas: Atlantic and Indian oceans.
Type locality: the Azores Islands (Sars, 1925).
Material examined:
3 females from samples: 379, 397, 457. See examined samples module.